Why detection of deception is an essential part of the law enforcement hiring process

With increased public scrutiny of police officers’ actions, police leaders must ensure they implement every check and balance when recruiting the next generation of cops

Hiring the right candidate, and ensuring that they continue to be clean, has never been more important in law enforcement. The Legal Aid Society, a New York-based nonprofit that is the largest organization of public defenders in the country, is building a “cop accountability” database, aimed at helping defense attorneys question the credibility of police officers in court.

In mid-2018, dozens were exonerated in Chicago because their cases were connected to corrupt cops. In this case, two officers were convicted of stealing money from a drug dealer – who also happened to be an FBI informant. This is just one case and is every chief’s worst nightmare.

With increased public scrutiny of police officers’ actions, police leaders must ensure they implement every check and balance available when recruiting the next generation of cops. Truth verification exams such as polygraphs and Computer Voice Stress Analysis (CVSA) can be useful tools in a department’s hiring process.

Law enforcement has much higher standards that must be met before making a job offer.
Law enforcement has much higher standards that must be met before making a job offer. (Photo/PoliceOne)

The problem is that smaller agencies often don’t have the equipment, staff or the funds to dig deeply into a new-hire’s background or determine if he or she lied on their application.

There are many companies that do background checks for private industry, allowing for basic due diligence by checking public arrest records and credit monitoring services. For an added fee, these companies may call the one to three references traditionally listed by applicants.

Of course, you know the above is not enough for a non-sworn applicant, and certainly nowhere close to what is needed for someone you are trusting to carry a sidearm to work every day while representing your agency to the public.


As the premier law-enforcement agency in the United States, the FBI relies heavily on polygraphs to ensure the truthfulness of its employees. Polygraphs are administrated to every FBI employee and job applicant. The bureau adopted the policy of administering them after the 2001 arrest of former FBI agent Robert Hanssen, who was convicted of giving classified information to Russia.

The FBI’s intention is not to smear candidates, but solely to determine if they are suitable for employment or pose a national security risk. The line of questioning will be discussed with the candidate ahead of time so that questions related to perfectly legal but possibly embarrassing actions can be eliminated.

Computer Voice Stress Analysis

Unlike a polygraph, which requires that the candidate, equipment, and a trained polygraph examiner all be in the same place at the same time, CVSA can be used over the phone or from a recording while interviewing a candidate and the information can be sent for analysis later.

Research into voice analysis began in the late 1950s when scientists identified a “physiological tremor” – tiny, involuntary oscillations in a muscle produced during times of stress. The first voice analyzer was developed in the early 1970s based on this research by three retired military officers.

While the FBI backs the polygraph, the validity of CVSA has been analyzed in the work of actual law enforcement officers documented in a paper titled, “Field Evaluation of Effectiveness of VSA in a U.S. Criminal Justice Setting.” A 2008 study funded by the National Institute of Justice (NIJ) notes that the mere presence of a VSA program during an interrogation may deter a respondent from giving a false answer.

Both polygraph and CVSA validity have been questioned and sometimes fail in lab studies. In fact, the associations of Polygraph Examiners and CVSA Operators each can point to case law where their technology was vindicated over the other’s. Which of these technologies should you use?

Sum of the parts

Background checks cannot rely solely on one or even two methods. All of the pieces need to fit together to inform your hiring decision. Polygraphs and CVSAs are best used within the context of the rest of the background process, once an individual's associates have been interviewed and records checks conducted. In this way, the polygraph or CVSA have three primary uses:

  1. To help identify correct information;
  2. To identify new investigative leads/routes;
  3. To encourage the applicant to be open about something they wouldn't normally disclose in a standard interview.

For point 1, when an agency has a significant amount of information on an individual, they can use the polygraph to probe deeper into grey areas. For example, if the background investigation determines that the applicant was fired from their previous employer, a polygraph examiner can dive deeper into the context of what actually happened to determine why and how it happened.

For point 2, when a polygraph or CVSA picks up on inconsistencies, this might prioritize something for further investigation. For example, if the applicant is answering a question about previous conflicts in the workplace and the polygraph flags an inconsistency, investigators can focus a follow up investigation on interviewing the applicant's previous co-workers.

For point 3, simply the fact that these tools are in use is enough to make many applicants open up about derogatory information. As the NIJ noted in its paper, the worry that a polygraph or CVSA will determine when an individual is lying is a powerful tool that should not be discounted.

Law enforcement has much higher standards that must be met before making a job offer. You could do a preliminary background check using one of the companies that specialize in the private sector then have your own personnel perform the rest of the checks.

Even if the applicant doesn’t have a record, you should pull more detailed interaction checks for places where the applicant lived or worked, which means looking up the various agencies with jurisdiction, like local, county and state authorities. You need to combine old-fashioned detective work with the latest technology to come up with a total picture of your candidate.

The Department of Defense’s Adjudicative Desk Reference, written to assist security clearance adjudicators, investigators, and security managers in implementing the US government personnel security program may be of help to your own background investigations.

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